With continuous progress of science and technology, various mobile terminals (e.g., mobile phones, notebook computers, tablet personal computers and the like) have been rapidly developed. Taking mobile phones as an example, with continuous improvement of user needs, the structure, style, performance and the like of the mobile phones are increasingly updated frequently.
Generally, an earphone hole is arranged in standard configuration of a mobile phone, and an existing extension key may realize an extension function through the earphone hole. Specifically, a plug of the extension key is inserted into the earphone hole to realize an electrical signal connection with the earphone hole. When a user presses the extension key, the state of an elastic mechanism in the extension key is changed to trigger short-circuit or open-circuit of a certain pin in the extension key, so that the electrical signal is changed. When the extension key is set as a photographing shutter by a user, photographing may be performed by pressing the extension key in a photographing interface of the mobile phone.